Either follow the Manual removal procedure

How to manually uninstall Symantec Endpoint Protection client from Windows 2000, XP and 2003, 32-bit Editions
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2007073018014248

or call symantec support or open a webcase and ask for the Cleanwipe utility.

Open your task manager.
kill all the msiexec.exe processes.
now uninstall using add/remove programs.
reboot the box and install it again.

Hi Kiran,

The Behaviour you have written is very unclear.

Please Let me know if you are carrying Windows XP Pro Sp2 or Windows 2000. There is no "Windows XP professional 2000 version."

Also, please attach a Screen Shot if possible.

Let me clearify,

Is that you are unable to uninstall SEP from your computer, and thyou receive a Black window which says that ,`windows is installing, please wait`.

Try the following things as I have understood the problem.

1) Go to the Task Manager> Process Tab > Check for "msiexec.exe' and Right Click on the process and Click on End process Tree.
2) Check for the same process int he entire list of Process and if you find, please repeat step 1.
3) If you still, have the same issue...go to Strat > Run> Type msconfig
4) Go to Startup  Tab, Click on General Tab > Click on Selective Startup > Uncheck the Box that says "Load Startup Items"
5) Click on OK
6) When Prompted, please Restart the computer.

Even after this you face the same issue, then Restart the computer in Safe mode and Run a Full Scan.

I would suspect the MSI installer subsystem is having problems--another product install might be to blame.  One example, I've seen Office try and reinstall before other applications can run, which was due to some MSI bug.

I like to thank everybody for giving me such kind informations regarding symentec end point protection problem.
Vikram ! I went through the link given by you and tired to follow the instructions. But, i found huge number of files to be deleted manually such as HKEY_LOCAL..........I am hesitated to delete these files because if i delete other useful files and ruin computer unknowingly,,please suggest me.......

As per advice of Mithun and Rafeeq, i opened the task manager and then process tab. I did not find any msiexec.exe file. The total files under process tab are given below

1. svchost.exe  (System)
2. SmcGui.exe  (Hari)
3. wuauclt.exe   (Hari)
4. alg.exe(Hari)
5. ashWebsv.exe    (LOCAL SERVICE)
6. ashMaiSv.exe(System)
7. iexplore.exe(Hari)
8. searchprotection(Hari)
9. ctfmon.exe(Hari)
10. ashDisp.exe(Hari)
11. WINDORD.EXE(Hari)
12. Yahoo Auservice.exe(System)
13. ash Serv.exe(System)
14. aswUpdSv.exe(System)
15. Ymsgr_tray.exe(Hari)
16. READSCTSERVI.......(System)
17. Svchost.exe(LOCAL Service)
18. SMAgent.exe(SYSTEM)
19. realsched.exe(Hari)
20. srchost.exe (NETWORK SERVICE)
21. Qttask.exe(Hari)
22. smc.exe(SYSTEM)
23. taskmgr.exe(Hari)
24. svchost.exe(SYSTEM)
25. mdm.exe(SYSTEM)
26. Sagent2.exe(SYSTEM)
27. svchost.exe(NETWORK SERVICE)
28. svchost.exe(LOCAL SERVICE)
29. Isass.exe(SYSTEM)
30. Services.exe(SYSTEM)
31. Winlog.exe(SYSTEM)
32. csrss.exe(SYSTEM)
33. smss.exe(SYSTEM)
34. explorer.exe(Hari)
35. Spoolsv.exe(SYSTEM)
36. svchost.exe(SYSTEM)
37. System(SYSTEM)
38. System Idle Process

I did experience similar issue. What I did was :

Repair SEP from the Downloaded CD1
Note : This will help the product to get installed correctly and if there was any missing or corrupt file will get replaced.
If you try repairing the existing installation from Add/remove programs it will use the cached install to repair and may not give positive results. If the cache is cleared then during repair from Add/remove programs, it may prompt to insert the SEP CD.

Once you are done with SEP Repair from CD - Restart the system.
You will not see the Installation window again.

Hope this resolves your issue :)

If fails I would recommend to call support.

Santosh.

Use cleanwipe to remove endpoint . then scan with nss.exe with latest definations.

after this try reinstalling sep. this may solve the problem. and also remember to install sep with admin login.

Hmm I am not sure that this is completely related to your recent install of SEP. Have you been installing a bunch of other software on this machine concurrently with the install of SEP (or even using windows updater). I recieved a similar error at one point after I reformatted my computer and was going through the process of installing ALL of my software. Essentially I was installing too much at one time, and while certain installs required reboots I would ignore these and continue to install other software to save the amount of reboots I would have to do. In other words I was in too much of a hurry ; ) I ended up just reformatting again because I could not seem to rid myself of the error and I figured it would be quicker than trying to fix it. For you however I would just test this by trying to install some other software and see if you get a similar error. Also don't forget to post back if you were installing a bunch of other software at the same time as you were installing SEP.

Cheers
Grant

I am agreeing with Bijay.Swain. Cleanwipe may solve problem(I had solved same problem using cleanwipe).You can use windows installer cleanup utility also for solving this problem. You can download it from below link. http://support.microsoft.com/kb/290301