Epson AcuLaser C900 Printer

What is the error that appear in the printer status on your computer?

The lights continually flashing indicate a paper jam or the printer being out of ink. Check/clear any paper jam and verify the ink cartidge is set correctly.

I have not used my epson aculaser C900 printer for quite some time, I have now reinstalled it onto my new computer. The green light and the red light are both on (not flashing) any idewas please

I have a similar problem with an old HP LJ1300. They have not updated the driver correctly and don't intend to fix it. I can't find any reference to AcuLaser C900 on Epson's support page. So maybe they stopped supporting the C900.

This is a duplicate of the question above.

check the toner ,, check paper jam and ,, paper tray ,, or any sensor issue,, don't give the print order untill you see the green signal over the printer...

Step1
Turn the printer off and on to see if it can automatically clear some or all of the jam. Many printers provide an error-code listing on the front panel display for the area where the jam occurred. If your printer shows an error code, be sure and check the printer manual to see if that identifies the area of the printer where the jam occurred. 
Step
2
Turn off the printer. 
Step
3
Remove any paper trays. Inspect them for wrinkled or damaged paper. 
Step
4
Open any other doors that give access to the printer's paper path and to the toner or ink cartridge. 
Step
5
If necessary, remove the toner or ink cartridge. Place it in a bag or away from light to avoid damaging it. 
Step
6
If you find a piece of jammed paper, remove it by holding it with both hands and pulling firmly (see A). The goal is to keep the paper from tearing. If several pieces are jammed together, try pulling out the middle piece first to loosen the jam. 
Step
7
If the paper does tear, try rotating the roller gears manually to free the paper (see B). Don't force anything, though. 
Step
8
Replace the toner or ink cartridge and paper trays, close any doors you opened and turn the printer back on. 
Step
9
If the printer paper jam message still appears, then there is still some paper in the printer. Reinspect the paper path.

This is the normal start up procedure. The green light will continue to flash until it has completed the startup/warmup rpocedure.

there is paper jam or there is the dust in some sensor

Yup, they are right (they usually are) this is what the service manual says: (see http://www.TheserviceManualShop.com for a manual)