Error 5

Every time I am trying to install software on my PC, I get the
following message:

unable to execute file in the temporary directory. Setup aborted

error 5: access is denied

ceci se produit depuis que j'ai effacé par erreur des fichiers d'une
clé usb. en réalisant mon erreur, j'ai essayé d'arrêter le processus
en appuyant sur ANNULER.
This has been going on ever since, a few days ago, I tried to retrieve
files found on a usb key that I had deleted in error. I pressed CANCEL
to stop the process

I run XP pro with an amd athlon xp 2600+ chip
60 Gb ROM
512 Mb RAM

Is ther anyone out ther who could help me?
.