Slow Application Load on Win7 64bit

One application which is used in our company is loading the executable very slow on Win7 64 bit clients. After I run the exe file I check the task manager. It is loading the first 30mb very fast (1-2 sec) but then it is getting really really slow. the remaining 30mb is very slow (more than 5 minutes).

I guess it is checking some dll files every time but couldn't find what to do.

it is working fine on any other 64 bit client (vista 64 bit etc).
it is also working normally on win7 32 bit.

the only problem is on win7 64 bit.

Can you please help me if you know how to solve it?

thanks.

Your too vague. You gave us nothing to do a search on; what is the application? If this was something you developed in-house then I would see if they could recompile and offer both a 32 & 64-bit version to see if that helps.

Also what Anti-virus do you use? If possible try removing the AV on a test machine and then open it to see if it has any effect.