Slow Performace,3D gaming/Encoding/Unexplainable things

Hello,I would like some help.on a few issues which I havent been able to fix up for a while now.

Specifications:

Intel Celeron 2.80Ghz - L1 8kb L2 - 128kb - FSB 400
Maxtor 6Y120PO 122GB (reads as 114GB in XP,and XP SETUP)
Seagate ST340014A 41GB (reads as 37.2GB in XP and XP SETUP)
1024MB DDR SD-RAM - Legend 512 400mhz - Generic 512 400mhz
^(Ram frequency Show 0.0hz in all Hardware info utilities,CPU-Z etc)^
Leadtek Nvidia 6600GT 128MB VM/114MB TM AGP 8x (shows AGP aperture size as 64mb..when i change in bios,it stays at 64.)
Generic Brand 400w PSU(26A 12v rail - 285 watts max on 3.3 and 5)
DVD COMBO and CD RW.

1.When i go to safe mode.The graphics takes really long to sync.for example.move the window it takes 3 secs to load the position.
2.When moving windows in.brings up cpu usage to 100%.
3.When encoding movies/avi files etc.12fps
4.When playing games..wow,CoD,War3.even the oldest games..i get a slow fps rate...i can set the detail on low..fully low..but its as if it was on high detail...no difference at all...FPS games..i look at the ground..and wow!! 60fp..the look um like 2 centremitres moving the mouse up even..my fps drops to (18-32)<one example.
5.When playing games..the game has like a slight 200ms freeze as soon as 3d graphics shows up.
6.VERY VERY WIERD!!!..did a dxdiag test with vertical sync on...i got 60fps..depending on my set refresh rate of course..60,70,72,75,85 etc..the fps stays there..then when i turn vertical sync off..and do dxdiag it shows a constant 999 fps...and the box is moving like turbo as..
7.When i have did a fresh install of xp..and intsalled the drivers first thing..and this still happens today btw..i install my nvidia drivers sound card drivers/lan etc...and in add/remove programs..there is no size shown for them..they are the only items out of everything i install that show no size..
8.My usb drivers are installed but still show usb hubs in device manager.and also when i plug my webcam in it displays just a green screen.so i have to keep unpluging it in and out for it to work.<tried new webcams not just one).
9.Also when my computer is on it interferes with other stuff..like my tv reception..

My monitor is a crt BTW and the video bandwidth of my monitor says 110mhz.
Dont know if thats an issue there or not.

Ok,cheers for your time guys,hope you can help me,I will be checking this thread regularly.

Thanks in advance,
Phil :cool

 

See try This first

http://forums.majorgeeks.com/showthread.php?t=115629

Studio T

 

I did that.but still the same problem.also i was checking the IRQ thingies so i got this
Conflicts/sharing part.

I/O Port 0x00000000-0x00000CF7 PCI bus
I/O Port 0x00000000-0x00000CF7 Direct memory access controller

I/O Port 0x000003C0-0x000003DF SiS Accelerated Graphics Port
I/O Port 0x000003C0-0x000003DF NVIDIA GeForce 6600 GT

IRQ 20 Microsoft ACPI-Compliant System
IRQ 20 SiS 7001 PCI to USB Open Host Controller

Memory Address 0xD6000000-0xD7FFFFFF SiS Accelerated Graphics Port
Memory Address 0xD6000000-0xD7FFFFFF NVIDIA GeForce 6600 GT

IRQ 16 NVIDIA GeForce 6600 GT
IRQ 16 CMI8738/C3DX PCI Audio Device

Memory Address 0xA0000-0xBFFFF PCI bus
Memory Address 0xA0000-0xBFFFF SiS Accelerated Graphics Port
Memory Address 0xA0000-0xBFFFF NVIDIA GeForce 6600 GT

I/O Port 0x000003B0-0x000003BB SiS Accelerated Graphics Port
I/O Port 0x000003B0-0x000003BB NVIDIA GeForce 6600 GT