Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Since this is OT I assume you are asking about Windows XP, which is totally obsolete. However the reasons for XP booting slowly could easily be a hard disk going bad, corrupted operating system/drivers, malware, poor network connection not picking up DNS, file crosslinks. I could go on but I think you get the idea.
The only anti-virus I know of that could work from DOS is NOD32. I don't believe Eset still offers it for purchase, unless it's part of their small business offerings. You may be able to find trial versions out there, but the trial versions likely won't let you delete the viruses you may find. Thus, the best thing to do is to update this machine's OS by installing something that is supported, like Windows 7. If that is not an option for whatever reason, save your data, wipe the computer, and reinstall Windows XP.