New Computer Set Up

I have a new comp w/Win 7 and some other programs instslled by the builder.
My old (an HP) also has Win7
I want to transfer some files from the HP. Then I want to clean the HP disc, and if possible leave the OP on it and remove any trace of me. (I think I read/heard some traces may remain - but I tend to doubt anyone would go to the trouble or expense to gleen anything I would have)
The new computer builder did tell me not to copy any of the OP's off the HPwhich coule cause problems.

I was browsing to find how to do this and now am really confused.
Where can I find instructions written on a level an addle-brained OF can understand.
Thanks,
Sarge

 

Uninstall the programs and delete the personal files you don't want on the old PC.
Then run CCleaner to first clean all the junk files, and then to wipe the free space. CCleaner > Tools > Drive Wiper. You can select 1, 3, 7 or 35(!) passes. 3 passes will be adequate for most home users.