Can i take the wifi from my dell optiplex 160l and put it in my acer computer?

You will have to buy one. It doesn't come with any card readers.

It's a matter of finding a compatible video card for your machine. In all likelihood, your machine will accept a PCI Express video card. Choose what size you'd like, (unless you're a serious gamer who requires a lot of vid memory, a 256MB or 512MB card will do). Then remove and unplug cables from your Desktop and pull out the tower. Remove the cowl and blank so you can add your card to the appropriate slot. Once the card is installed, plug everything back in and turn the machine on. Since it's Plug n Play, your machine will automatically identify the new hardware. At this point, uninstall your previous video hardware in the Hardware Manager and install the new card either by downloading the driver online of if provided, use the disk that should have come with the new card.

A Dell 160I is a printer, as far as I know. They don't come with video cards, although many modern printers have a small LCD display.
Apparently yours doesn't have this.
If you don't have it, then you're stuck with what you have.

See http://support.euro.dell.com/support/edocs/systems/op160l/en/ug/smtabout.htm#1189371 which is the Dell Optiplex 160L User Guide and shows the internal layout of this computer with instructions for removing expansion cards.

Since you can't upgrade memory on a video card especially if its built on to the motherboard your best bet is to purchase a new PCI video with the proper amount of memory you need and install into your dell PC. you may have to go into the BIOS and disable the on board video card and tell the system to use the new one. Just make sure the new card you purchase has drivers for whatever operating system you are running.

HDD Controllers are IDE
http://support.dell.com/support/edocs/systems/op160l/en/ug/specs.htm#1135527

Listen to the pattern of beeps, or look at the back of the computer to see the pattern of the diagnostic lights ( 4 lights just under the keyboard/mouse connectors) and check out this site to see what they mean:
Beep Code Meanings
Diagnostic Light Meanings

Here is the download page, you need to select model and OS: Driver & Download

It could be that the processor your trying to upgrade with is bad, try another CPU to make sure.

Hi there is one more thing you should check before buying another mobo. Trace the wires from your on/off switch on the case, unplug it and then bridge the 2 pins out with a screw driver, this will start the computer. runit as normal, then shut down and see if you get a restart. If the computer does not restart on its own you have a faulty switch. Clean it or replace it. Regards mistyman