How do I check an uploaded file for viruses?

Could someone please tell me how to check if an uploaded file has a virus?

[siasm]

Question: Could someone please tell me how to check if an uploaded file has a virus?

Background:
I have created a basic website and found some instructional code for uploading/downloading files. Please note, I'm not referring to the sending/receiving of emails, I am referring to uploading/downloading of a files (eg a word document).

The files will be uploaded by one user, stored in a MySQL database and downloaded by another.

As my site is an internet website, sooner or later a user will upload a virus. I want to prevent (as much as possible) the virus being downloaded onto another users computer.

Website details:
- shared hosting,
- Windows operating system,
- ASP code and
- MYSQL database

I would really appreciate this help, as I would like to offer this feature - but I want to offer it responsibly.

Thanks.

[cmatcme]

I suppose you could upload a small virus scanner and you may be able to get a program to get it to run or you could check the database manually depending on how popular your site is.

Seeing as you have ASP, it may be better in forum 47. [webmasterworld.com]

[siasm]

Although the website is currently in ASP, I am willing to consider any solution.

I recognise I could download each document to my personal PC and virus check them.

However this would add:
- an additional turnaround time to check each document
- the risk of infecting my own PC and
- a lot more work for my PC as the functionality took off.

[txbakers]

When you upload a file, it needs to reside in a directory on your hard drive.

Schedule an Antivirus run for every 10 minutes, only on that directory.

It will run pretty fast, and will catch/delete/quarantine any uploaded file with a virus.