Where is the printer hookup on this computer?

Charles, has this combination worked previously, have you been able to print from your Dell Dimension 2400 to your HP Deskjet 3070A successfully?

If the answer to the above is Yes, then if you believe that the printer is still working correctly and you can test this with a different computer able to print to it, you should consider uninstalling and re-installing the HP software and device drivers for this printer.

If you have not printed to this printer successfully previously, have you tested the printer with a different computer and proven it is still working fine?

If the printer works fine to a different computer then providing you are using the same USB cable to connect to your Dell 2400, the problem needs to be narrowed down further.

Check that you can plus other USB devices into the port on the Dell used for the HP printer - if these work, then your USB port is good - if not, try another port if you have one.

If your USB hardware is good, then again you are left with the need to uninstall and re-install the HP software and device drivers - it may be worth trying to download the latest version of such software if available. HP tend to update their All-in-One software on a regular basis.

Try this website..this is a manual for Dell Dimension 2400 PC Desktop
it includes how to remove the cover of your tower. Check it out..
http://www.andovercg.com/datasheets/dell-dimension-2400-series.pdf

The safest option is to reinstall Windows. And next time pick a better antivirus.

You can either use a dvi or vga cable, for more info go to http://service.gateway.com/s/Manuals/Monitors/8511253.pdf

Run your anti virus and anti malware programs. If you do not have a anti malware program go to cnet.com and download a free anti malware program. It sounds as if you have a virus on your computer

Your sister has a vivid imagination. Changing the memory and flashing the BIOS will chane nothing.

If you want to start from scrath then reformat the hard drive and reinstall the system but as you probably don't have a system backup disc this will prove impossible for you.

Your best bet is take it to your local PC shop (I don't mean the mainstream ones) and they will be able to restore your system.

You've learned a valuble lesson the hard way here. Always have a good antivirus programme installed, make sure it is up to date and do a full scan on a regular basis.

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it might caused by virus, you initially need an good virus remover with updated defination file. first scan your computer, if you found any virus you might need to re-install windows. if there was no virus then un-install yahoo msgr first through control panal, then re-install the same by downloading through yahoo site.

You will need to try a recovery disk or a working version on windows XP or Vista to boot from and repair, or format hard drive.

check inside the case of the computer to make sure that the interface cable between the hard drive and the motherboard are fully connected. Also check to see if the RAM modules are fully inserted into their slots. If not, they try removing them one by one, until the computer starts up faster. If this doesn't fix it, then try a new hard drive, and interface cable.