Is there a virus that causes the computer to beep every 15 minutes or so?

According to the following URL about NETSKY.C VIRUS it does indicate a virus: mcafee.com

Indications of Infection:

Audio payload - On Feb 26, between 6-9am the worm makes random beeping sounds with varying pitches and rhythm. Sound byte

Existence of files and registry keys as mentioned above

Unexpected network traffic

Outgoing DNS queries to one of the following hard-coded IP addresses: 145.253.2.171 151.189.13.35 193.141.40.42 193.189.244.205 193.193.144.12 193.193.158.10 194.25.2.129 194.25.2.130 194.25.2.131 194.25.2.132 194.25.2.133 194.25.2.134 195.185.185.195 195.20.224.234 212.185.252.136 212.185.252.73 212.185.253.70 212.44.160.8 212.7.128.162 212.7.128.165 213.191.74.19 217.5.97.137 62.155.255.16

I would suggest getting a virus program such as AVG from Grisoft. They have a free version available. It works great. It will detect any virus you might have and heal any it can. Those it can't heal, either turn off system restore or for some you can remove with an alternate program that AVG has developed:

To remove I would suggest visiting the following URL from Grisoft/AVG: grisoft.com

I would suggest following its instructions to the letter. If you do, you can then run AVG again and the Virus will have disappeared.

Good Luck!