Updates and applications installed using Windows Update will always be digitally signed by Microsoft. The signature allows you to verify where the code came from and if it has been tampered with since its publication.
Unfortunately, both the programs you have installed are a complete scam and have nothing to do with Microsoft. Both programs use scare tactics to try and intimidate you into buying them. AlphaWipe is a suspect history cleaner, creating fake alerts about problems with your PC's registry that don't actually exist. XP Antivirus 2008 uses similar tactics by generating its own fake system error messages, which pop up and try to coerce PC users into buying the program in order to remove them.
You say that you downloaded these programs from your Windows Update icon. If this is the case, then it sounds very much like other malware is resident on your PC, which has changed where the Update icon takes you. I've also read instances where people have been duped into installing these programs while trying to purchase genuine antivirus and antispyware. So, sadly, you are not alone. Malware often comes bundled with free software downloads. It can also install itself when you use file-sharing functions found in instant message programs or visit a malicious website.
You need to first safely remove both of these programs and any other malware on your PC. There are many trusted antivirus and antispyware programs you can use from vendors such as Symantec Corp., McAfee Inc., and Kaspersky Lab Inc. If you don't want to spend any money, AVG Technologies provides a very good free antivirus program. SpyBot - Search and Destroy, a spyware tool, can also be downloaded for free..
Download, install and run both of these programs to remove what will probably be a large number of malicious applications that have infected your PC. Once you have done this, I would go to SpywareRemove, an online spyware removal guide, and check that the files they list as being part of XP Antivirus have been deleted. The next step is to restart your PC and run both the antivirus and antispyware programs again to ensure that no unwanted programs have reappeared.
Once you have cleaned your PC, it is very important that you practice safer online habits to prevent being infected again. If you get an unexpected window popup on your PC, close it by clicking the cross in the top right corner. Often malicious popups will have what appears to be Yes and No buttons. No matter which button you click on, a download starts, installing a malicious program on your system.
Do you use a peer-to-peer (P2P) program or other applications with a shared network? When you use these applications, you put your system at risk by possibly and unknowingly downloading an infected file. I would also ensure your Web browser's security settings are not set too low. If you're using Internet Explorer, go to Tools then Internet Options. On the Security tab, you should have the Internet setting at least at Medium-high. Depending on the types of site you visit, I would even consider setting this to High.
SearchSecurity.com has lots of advice on safe surfing, including a spyware removal checklist, an FAQ on spyware and malware, and a free Intrusion Defense School. I would suggest that you read these articles about protecting yourself -- and your organization -- from spyware and other malicious programs.