Hello Muhib --
welcome to FixYa.
Your HP Laserjet 2100 has many ports and ways of printing
1) irDA -- infrared port ... only works when computer is within 1 meter and 15 degree angle line of sight. -- Infrared way
2) Parallel port -- PC compatible way
3) LocalTalk port -- Macintosh way
In addition, you might print with PCL (HP's proprietary Printer Control Language) or this PS (Adobe Postscript) language.
Depending upon how complex your documerts or graphics are, it could take a while to queue and print your page as the printer has very litle internal memory installed. You can add more printer memory. DIMMs are available in 4, 8, and 16 MB, for a maximum of 52 MB, however the cost of the memory chips may exceed what it takes to purchase a more modern printer that already has enough memory inside.
If you have Windows, then I would recommend that you check your printer driver. If it is a Postscript driver, then try removing it and installing a PCL driver instead.
Muhib, I also recommend that you download the manual for the printer.
It may also benefit you to choose an up-to-date driver from the HP