So I tried putting this motherboard, Biostar A880G+ in a Dell Dimension 2300.
What I've already upgraded also:
RAM to DDR3
adapter to turn IDE HDD into a SATA connection
CPU to AMD Athlon II X2 245 Regor 2.9GHz AM3 65W Dual-Core
stock heatsink from an AMD Phenom II x6 1090T
Unfortunately, the board has a 24-pin socket for psu connection, whereas the Dell psu has a 20-pin connector. All I've read so far is that this shouldn't be a problem, "unless it's a Dell psu-" then maybe there will be a problem.
I hooked everything up, and it wouldn't power on. Literally, I pushed the On button, and absolutely nothing whatsoever. It didn't even try to power on. Is there anything else I could check? What can I do??? 
What I've already upgraded also:
RAM to DDR3
adapter to turn IDE HDD into a SATA connection
CPU to AMD Athlon II X2 245 Regor 2.9GHz AM3 65W Dual-Core
stock heatsink from an AMD Phenom II x6 1090T
Unfortunately, the board has a 24-pin socket for psu connection, whereas the Dell psu has a 20-pin connector. All I've read so far is that this shouldn't be a problem, "unless it's a Dell psu-" then maybe there will be a problem.
My Computer
- Computer type
- PC/Desktop
- OS
- Windows 7 Pro x64 SP1
- CPU
- AMD Phenom II x6 1090T Black Edition 3.2GHz
- Motherboard
- ASUS M4A88TD-V EVO/USB3
- Memory
- Patriot G ‘Sector 5’ Edition 8GB (2 x 4GB) 1600MHz
- Sound Card
- (onboard) Realtek® ALC 892 8-Channel High Definition Audio
- Monitor(s) Displays
- ViewSonic VX2253 22"
- Screen Resolution
- 1920x1080
- Hard Drives
- Transcend SSD720 2.5" SATAIII 64GB SSD; Western Digital Caviar Green WD20EARS 2TB 64MB 3.5" HDD
LG WH10LS30 10X Blu-ray Burner with LightScribe
- PSU
- CORSAIR TX Series 950W ATX12V 80 Plus Bronze
- Case
- Cooler Master HAF X NVidia Edition; 5 Green LED Fans!
- Cooling
- CORSAIR A70 120mm Dual-Fan
- Keyboard
- Verbatim 97472 Mini Wireless Slim
- Mouse
- bundled Verbatim 97472 Wireless
- Antivirus
- Avast
- Browser
- Chrome
- Other Info
- Ultraportable/Desktop Replacement Laptop:
circa Oct 2006,
Dell XPS M1210,
Windows 7 Professional 32-bit,
Intel Core 2 Duo T7200 2.0GHz,
3.25 (4) GB of RAM,
NVidia GeForce Go 7400,
500GB Seagate Momentus 7200RPM HDD