Internet explorer issue

Hi,

I am not able to open internet explorer in windows xp sp2 system.
I did the following things

1. Repaired the os (While repaireing IE8 beta2 is installed)
2. Reinstalled IE7. It has shown that installation has completed.
3. When ever i am trying to open IE nothing is happening.
4. Expanded inetcpl.cpl from windows xp cd to c:\windows\system32 folder also.

Any one can help in this regards?

Thanks,
knagaraj