Lenovo Thinkcentre Problem?

I've changed the CMOS battery of my Thinkcentre like I did many times on my assmbled pc.
after this my computer stops booting and says no os found.
then I set the bios to default but again noting happened.
I enabled the AHCI settng on bios then it comes to booting opt(safe mode.last known good con netc)
after selecting all of them my machine restarted.
then I disabled the AHCI after that machine started normally but when i started my machine the next day the problem comes again.
when I rechecked tha bios I found the HDD on the bottom of the boot sequence I tried to move it to the 1st opt but nothing happened whereas when I tried the last method I told it works bt when I restarted my pc the same problem occurred.

Lenovo thinkcentre m55 drivers for xp?

I'm looking for xp drivers for the computer mentioned above. Does anyone know where to find them? I'm missing video driver, sm bus controller and the audio controller. The lenovo websight doesn't have these

Where do i download free software for a IBM Thinkcentre?

I have an IBM thinkcentre desktop computer and i need to install the video controller (VGA compatible), audio device on high definition audio bus, and video controller where can i download what i need parts unknown, or where can i find this info.

Does anyone own a Lenovo computer?

I'm a graduating senior and I'm searching for a new laptop. Now I want a Sony Vaio or HP Pavilion. (Well really I want a MacBook, but that's another story.) My uncle, who works for a computer company is offering me a deal on a 15.4 Lenovo computer. I'm sure what its official name is but these are some of its specs:

Levono 15.4-Inch Laptop with touch sensisitve surface and built in subwoofer.
> CPU Type - Intel Core 2 Duo T5900
> Screen - 15.4" WXGA
> Memory Size - 4GB
> Hard Disk - 250GB
> Optical Drive - Dual Layer DVD Burner
> Graphics Card - Intel GMA 4500MHD
> Video Memory - shared memory
> Communication - Modem, LAN and WLAN
> Card slot - 1 x Express Card
> Battery - 6-cell lithium ion, Life 4 hours
> Dimensions - 14.20" x 10.30" x 1.10-1.40"
> Weight - 6.4 lbs.

He's offering me and my mom a cheap deal, understanding that money is tight for us. But I really want a Sony, HP or even a Mac. Should I accept the Lenovo? Does anyone know about them?

Replace grahpics card ThinkCentre S51 (type 8172)?

I got this box like computer ThinkCentre S51 (type 8172)]
http://www-307.ibm.com/pc/support/site.wss/MIGR-58587.html
Can I replace the graphics card for a more suave one? Memory is cheap and i was thinking of making it gaming worthy.