DDR2 PC2-4200,DDR2 PC2-5300,DDR2 PC2-6400 with a maximum of 1GB per slot (equals 4GB max total system memory)
no it will degrade your system
NO
Yes
Unfortunately you can not. DDR and DDR2 have a different pin arrangement and they will never work in each others slots.
The Acer Aspire 3620 Notebook computer can use DDR2 PC2-4200 (DDR2-533) or DDR2 PC2-5300 (DDR2-667) which are 200-pin SODIMM modules. The Acer Aspire 3620 has two memory slots and each slot supports up to 1 Gigabyte of RAM for a total of 2 Gigabytes. This system uses unbuffered, Non-ECC, 1.8 Volt RAM.
No, you cannot. PC2 is ddr2 type of memory when PC is ddr. Those types are not compatible.
Yes. They are backwards compatible. Even with the installed 800MHz ram It will still only run at 667MHz speeds.
Although it would probably be possible, depending on the chipset used, it would offer poorer performance.
The Dell Inspiron 9300 takes DDR2 PC2-5300 SODIMMs. It has two slots, each of which can hold up to 1GB, for a total of 2GB. This memory should work in your laptop with no issues, however, for performance issues, it is recommended to have the same memory size and type installed in each slot.
Is a memory of 256 Mb
From this site, http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00280659&lc=en&cc=us&product=447312&dlc=en, the slot on your computer is for DDR which is 184 pin, DDR SDRAM. That means you cannot use DDR2 rams because DDR2 has 240 pins and it will not fit on what your computer has.