I have a hp psc 2410 .the black is printing beautifully but the colour it printing doubled or blurry. changed colour cartridge and still the same. help please

Your inkjet nozzles may be clogged with old dried ink. Try removing your color cartridge and looking at the area on your print carraige where the inkjet cartridge mates up with the carriage. Use a Q-tip and warm distilled water to gently swab this area until all the old ink is dissolved and it wipes clean. You may need several Q-tips for this. Allow to air dry and reintall your print cartidge. Your printer should go into an automatic cleaning cycle. You may also need to gently clean the area on the cartidge itself using the Q-tip method. Good luck.