How to Upgrade to max RAM

nope

You need "PC3200 DDR SDRAM" memory. You will be able to add a 1GB module max or you can remove your old ram and put two 1GB modules which I recommend. Example: http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3486310&CatId=1838

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).

This laptop can support up to 4 GB or RAM.

it must be DDR type of Ram. dont use DDR2 ram.

you can use 1 GB DDR of Ram

Hi,
The first models of acer aspire one pro P531h-0Bk is not able to get more than 1gb RAM, but the revised model is able to get this. So you MUST consult with your IT dealer.

You can upgrade your Hard disk.

There are lots of possibilities Rob. Endless, I would say. Looking at your specs you could spend up to $400 or $500 depending on what you want.

RAM - $50 to max out @ 4GB
Graphics - $100 to $200 for a good PCI-Express card w/512MB
Sound - $50 to $100 for a good 7.1 card
CPU - $100 for a Pentium Dual Core 2.7GHz with 800MHz FSB

These prices are from www.tigerdirect.com which would be a good place to start.

One thing to consider is the price of a new computer compared with an upgrade. Sometimes you are better off just getting a new one. Again, it depends on what you want...and can afford.

Good luck and thanks for using Fixya.

According to Acer your system can support a max of 4 gb RAM. It has 2 slots so you would need 2, 2 GB RAM modules. Hope this helps & please remember to rate my answer. Thanks.

Thanks for choosing fixya.com

Your not alone in this type of problem. When it comes to computer (laptop especially) they usually have a "Max allowed ram" most times its listed in the back of the manual in small print. Its a way to keep people buying new computers (if your into the conspiracy theories)
Chances are even a bios upgrade would not fix your problem. Mostly BIOS upgrades add support for new boot options, plug and play support, and fixes to bugs in older versions.

You can check aspires/acers website for updates www.acer.com
If they have an update it will comes with documentation as to what the update does.

Hope this helps you out.
Jei