Hi frnds ... i had 1 gb ddr2 ram but now i've installed vista x64 for this i also installed 2 gb ddr2 ram slot (total 3 gb) but when i start my pc it says.... new hardware found ...upgrade ur BIOS ... so guys what should i do?

You should be able to as it can take 4 gig total according to the manual.

Memory:
2 DDRII DIMM memory slots (supports up to 4 GB memory) (Note 2)
Supports dual channel DDRII 667/533 unbuffered DIMMs (Note 3)
Supports 1.8V DDRII DIMMs
Note 2. Only for GA-945GCMX-S2.
Note 3. Only for GA-945GCM-S2.

No. The maximum that your motherboard will support is 2 GBs of RAM. 1 GB on each slot. Refer to this link: http://www.crucial.com/store/listparts.aspx?model=D945GCNL

Your RAM needs to be:

DDR2 667, DDR2 533 or DDR2 400 MHz SDRAM DIMMs

Non-ECC DIMMs

2 GB maximum total system memory

Unbuffered, single-sided or double-sided DIMMs with the following restriction: double-sided DIMMs with x16 organization are not supported

Make sure the New RAM is not bad.

Ensure that the new RAM is the same type as your old one (DDR2 XXX)

Install the old one back and make sure that your PC works.

If it does, Take the Old RAM out and install the New RAM in the same slot as the old one.

If the PC does not work with the new one, It is more than likely a bad stick of RAM

Hope this helps

Your laptop's RAM is upgradeable to up to 4 GB using two DDR2 533/667 MHz SODIMM modules.

So your upgrade options here are:
1. Buy a 1 GB DDR2 533/667 MHz SODIMM module & install it to get a total RAM of 2 GB (Price around US$ 25).
2. Buy a 2 GB DDR2 533/667 MHz SODIMM module & install it to get a total RAM of 3 GB (Price around US$ 45).

From what I read on their site you need 1 stick of DDR2 memory built for 2GB. Open the machine and see how many memory slots you have. The site said 1 but sometimes there are 2 slots for them. If there are 2 slots but only 1 is filled then you need 2 sticks of ram built for 1GB each. If there is only 1 slot then you need 1 stick built for 2 GB. Pop the old RAM out and install the new RAM. Power the system up.

max ram per slot is 1gb, for 2GB total. A 2 GB module will not work

http://www.crucial.com/store/listparts.aspx?model=Aspire%204315

Here are some instructions that should work for all 3000 series laptops.
http://support.gateway.com/s/Manuals/Mobile/8512061_Apache_RPL.pdf

DDR 1 - 1 GB costs around Rs 1500 DDR 2 - 1 Gb costs around Rs 1200 DDR 2 - 2 Gb costs around Rs 2200
I just upgraded my system to 2 Gb ddr2.
You can order it on ebay.

1. Shut down your computer & unplug the power cord.
2. Try cleaning the slot where the RAM module did notwork using non-oily contact cleaner spray.
3. After spraying the cleaner into the slot, use a brush made of animal hair to clean the slot.
4. Leave it for about 10 minutes to make sure that the liquid totally evaporated off the slot.
5. Install your memory module & power on the PC to test.
6. If it still did not work, swap the 2 memory modules & try again.

Feom the Gateway site: 2048 MB 533 MHz DDR2 SDRAM (2 × 1024)
Total slots: 2 DDR2 slots | Available slots: 0 DDR2 slots
Maximum memory: 2 GB
Hope this helps.