Programs doesn't start in windows 7

[KALLIYAN]

I got this very strange problem with my computer. I am using Windows 7 Ultimate 64 bit edition. Whenever I start my computer it comes on fine without any problem. But when I try so start some applications or program it doesn't start at all. It shows like it is starting but doesn't come up actually. I see the hourglass when I try to start the program. A very simple program which I try is like Windows Media Player, IE, Windows Media Center and many more.
When I checked the processes list in task manager, it shows that the program is running.
What can be the problem.?

[SalVatore]

Now as you have mentioned that many of the programs doesn't come up but are there in the processes list. So over here it can be some issue of virus, it is possible that your computer may be infected with a virus. The ISO which you got was that proper and was it clean.
Because there are some virus which hides the process in the taskbar and we are not able to see it running on the screen. So you see there are many possibilities, and don't take any tension even if its a virus issue then too it can be solved without any problem.

[KALLIYAN]

I don't know if the ISO was infected with any virus or not. But I tried the same ISO on a friends system and it worked fine without any problem. So it should work fine on my system also right.?
I tried 32 bit version also but that also did not work for me. So I actually am confused of what is happening. I am not able to use my computer. What should I do now. Can some one please.?

[Dr. V]

Now I guess there may be some issue with your HDD. Check for errors on your HDD. Because if you wipe your HDD before installation then run scandisk with fix errors and never override installation on a Bad Windows 7 operating system because it creates more problem.
So if it is still installed then run scandisk from command prompt and check for errors.

[KALLIYAN]

I checked the HDD for errors, but didn't found any. I then installed Windows vista on one HDD and windows 7 on another HDD. Vista works fine withoug any problem. And Windows 7 also worked fine at the start. I opened IE and it came up. I then after surfing on couple on sites I closed it and reopened it but was not able to. Again same problem.