Lazer probs

[elkayps2]

I have a 30002R pal console I have installed a R-Mod, It worked fine up untill the other day. now when I play some dvd-r titles I can boot them fine allthough when the ps2 needs to access allot of data at once on the disk during gameplay (GTA3) it freezes and displays a "dvd disk read error"

sometimes whan I have tried to boot some dvd-rip games I have heard strong, errrrrr louder than normal ticks coming from the ps2 dvd-drive,

the mod worked 100% for a couple of weeks...

is it possible that I have damaged the DVD laser?

whats involved in a lazer re-allignment?

Plaese help