1) All four of these sites download ActiveX controls to your computer, so they require Microscruffie's Internet Explorer Browser, version 4 or better, and a Windoze OS. Except for Housecall, they won't run with other browsers so far as I know.
2) These sites check each and every single file on your hard drive so, if you have a lot of files, they are sssloooooww. But free.
3) All four scan for viruses and trojans, but each has at least one unique service as well.
Symantec and Pitstop only check for viruses, they don't repair. They are included because they are the industry heavyweights.
| SymantecCheck | 1) Viruses and trojans (detects only, doesn't repair). 2) Check computer's vulnerability to invasion from off the internet. 3) Trace potential attacks and origins of spam mail (!!). 4) Frequency of updates to their virus/trojan database is unknown, but Symantec is a good outfit. |
| Pitstop | 1)Viruses and trojans (detects only, doesn't repair). 2) Computer performance measurements and suggestions to improve overall performance. 3)Virus/trojan database updated only monthly. |
| PandaScan | 1) Viruses and trojans. 2) Disinfects, renames, or deletes detected viruses/trojans (!!). 3) Database updated daily. |
| Housecall | 1) Viruses and trojans. 2) Disinfects, renames, or deletes detected viruses/trojans (!!). 3) Works with Netscape 3.01+ as well as with Internet Explorer. |