Printer Printing Crooked!

Most likely to be a page feed problem, look online to clean page feeder rubber rollers.
Try here for the pdf manual which covers problem with jams and skewing
http://www.hp.com/ctg/Manual/c00264334.pdf

May be bad toner cartridge or the laser is dirty (clean laser for better image)

Well this issue must be related to the drivers of the printer, possibly incompatibility. Let's try to fix it with the easiest method.
First uninstall the driver after the printer is disconnected from the computer. Then run a registry cleaner (click here to download a freeware registry cleaner) to clear any unwanted registry files. You'll also need to clean the system using the feature with this application.
Now download this driver Hplaserjet 2100 windows vista32 (if your system is 32 bit) or hplaserjet 2100 windows vista64. Extract the files to a specific folder and follow the instructions as follows;
Click "Start" , select "Settings/control panel" and click the "Printers" folder.
Double-click "Add Printer".or click "File" on the menu and select "Add printer"
The "Add Printer wizard" will open. Select "My computer" then click "Next".
Select LPT1 (whether directly connected or networked) and click "Next".
Click "Have Disk".
Click "Browse".
The Locate file window will come up saying a: "is not accessible" . Click "Cancel".
Under "Look in" select the folder where the file is saved.
Highlight "HPLAOUT.INF" and click "Ok".
The Install from Disk window will reappear, click "Ok".
Select "HP LaserJet 2100 Series PCL 6" and click "Next".
Select the "Replace existing driver" option and click "Next". (This window will not come up if the uninstaller was used).
Select Not Shared and click "Next" .
Select "Yes" and then click "Finish".
Please don't skip even a step from the uninstall process. And do let me know when you are done.

Till then, Good luck.

Thanks for using FixYa.

my printer has only print hp test paper but not printered a computer file print

Does this happen when printing from the cassette (bottom tray), or the sheet feeder in the back, or both? Check that the paper guides are set snugly (touching but not buckling the paper) against the edges of the paper.

The "nonsense" is your printer trying to interpret the information. Go to HP.com and download the correct drivers. Delete all other drivers from the Printers and Faxes/File/Server Properties. Then install your correct print driver

it is due to crack in teflon sheet in printer. change it. it will work

How old is your toner cart?
Have you given the toner a little shake lately?

Is there paper wrapped around the fuser causing only a partial printout?

I would recommend a good cleaning of the rollers with a damp rag (old t-shirts are great for this). Some canned air to blow out the insides always seems to improve operation. 
If this is helpful to you, would you please rate this solution? Thanks!

I had exactly the same problem, printer virtually new, printed great for a couple of weeks, then today refused to take paper with E3 flashing. No apparent blockage - all looked clean, tried all the utilities, roller cleaning and plate cleaning, but wouldn't take paper!
Solved it by moving the paper size guide all the way to the left, then folding the top 20mm of a sheet of A4 over and loading it so fold is at the top facing you. This acts as a catcher for anything stuck in the printer. Hold the paper slightly crooked with the left side slightly further into the printer and press the copy button (with nothing in the scanner!). It should draw the paper in now (with some persuasion) and think it is printing (it's blank,of course). Check as the top of the sheet goes in that the fold is still tight and doesn't open up as it feeds in. Lo and behold, mine brought out a 5p piece - printer now prints perfectly!