This is my section on media players.
FileHippo list of MultiMedia device
This is your best bet as you while find most good free media players here.
Running on my desk top...
It's free of course, and will play anything I can throw at it.
There are plenty of add-ons too, such as skins, device and languages.
http://www.winamp.com/ but download it at Filehippo, here...
VLC Media Player from VideoLAN
VLC is a free and open source cross-platform multimedia player and framework that plays most multimedia files as well as DVD, Audio CD, VCD, and various streaming protocols.
Checked April 2014 for links and relevance to Windows XP and Windows 7.
This is my site for links to Genuine Free Stuff as well as some useful advice. I use most of these programs regularly. It's good gear. It's all worth having.
** April 2014. Major revamp and update for relevance happening, especially now that support for Windows XP has ended, and now that we all are addicted to our Android phones. A lot of old stuff is going.
This post in particular started this whole website...
I have been building and using computers since about the Ice Age, from DOS 3 through to Windows 7.
I have been mucking about with mobile phones for quite some time, using Symbian S60 and then Android.
Press F8 at boot to start in safe mode - Windows XP and 7
To see the details of you computer, download, install and run 'Speccy' - shows Operating System, Firewall, Anti-virus and hardware.
If you think you have a virus, start here 'Free Online Virus Scan'. Try any or all, and be patient.