It has a problem with the program and i deleted almost all of it files.When i open the application it says "A previous version of S2PCI You have to uninstall old version first!Do you want to do it now?" And i click Yes and then nothing!I desided to go to Start>Search and type S2PCI and there's one file in C:Windows/Prefetch >SIMS2PACKINSTALLER_V1514.EXE-3301DD53.pf .Do i have to delete it?Is it gonna work when i delete it?Is there another way to re-install the program??

Please read the sticky at the top of the forum:
http://www.modthesims2.com/showthread.php?t=217787

Ok,really sorry....

Hehe- it's okay- I was just trying to get you to try that first! Did it work?

Nope.I don't have these files.

They aren't files, they are registry keys. Did you check your registry?

Aaa,no.I don't know where do find them!I searched in C/Windows for Registry but i don't have!Can't find them

You access the registry with the regedit tool
start/run type regedit then enter...choose the key to delete :
hkey local machine/software/sim2packclean installer

Be careful with this tool, you can kill you whole system !

Oh,do i have to back up my registry?I'm a bit confused,if i mess something ,my computer will be broken... *afraid*
Thanks for helping though.

Yes, follow exactly the instructions of the link simsample give you.

Not difficult at all but a bit dangerous.

Do i have to backup my registry?

I hope it is useles but yes, in files menu choose export, give a name and proceed.
the do your changes.
If you made a mistake double click on the .reg file you created before, it will restore your registry.

Hmm i open the program and paste this "hkey local machine/software/sim2packclean installer" and it says that can't find it...

follow the tabs letf side of the screen, select local_machine then in opened tabs software etc to find and delete the keys