Crypto\RSA\S-1-5-18 folder infection?

[Guest Lynn]

Win SBS 2k3 Standard. My A/V occasionally flags files in this folder

(C:\D&S\All Users\App Data\MS\... )as infected but does not specify the

infection. I had questioned my local gurus at one point and was told to not

worry about it. Files are usually deleted when found, before I know about it.

Had one show up today, couldn't disinfect or delete so quarantined it. I'm

trying to read up on what this folder is for, and will be submitting file to

A/V company for research, but thought I'd post questions here concurrently.

What is this folder for? Should I even be scanning this folder or should I

exclude from A/V scan? Should I be *extremely* worried or just worried that

this happens from time to time? Ideas on possible infection vectors? A/V is

current, have run anti-malware programs and even rootkit detector in past

when this has happened, system shows clean. Thanks!