AMD Athlon 64 X2 6000+ High Temp!

Have you reapplied thermal paste recently? That would be my first step. I had one with a thermal right 120 and it never got above 45C.

What are you using to monitor the temp? If it's a program that came with the motherboard it is probably pretty accurate, but many programs out there will give wildly different readings.

my old laptop amd cpu reached his shutdown trigger temp of 102C... so on my opinion, the temp is ok.

Windsor core is more hotter than others. Do these things:
1) You need to clean/blow away dust from the CPu fan.
2) Connect another two fans with 3 pin to the chasis connectors provided on the motherboard.

Have you thought about getting a new CPU Cooler. I use to run an Athlon 6000+ and then switched to a Phenom II 940 (another 125 processor). Had what seemed like high temps with both (idle around 50 max in the 60's) until I switched my CPU cooler. Tried about 3 aftermarkets without much difference but then I got a Xigmatek S1283. This dropped my temps WAYYYY down. I now Idle in the low 30's and max in the high 40's. After putting a Xigmatek on my Phenom I built another system around my old Athlon 6000+ and put the same Xigmatek in that system. Temps dropped to the same range as my Phenom. Had been running the Athlon 6000+ for over a year at the high temps with no trouble but if you want to drop your temps look at a Xigmatek cooler.

While going thru this process I also thought that more airflow in the case would help. I went thru 3 cases (Last two where Thermaltake Armour MX+ and my current an Antec 1200). While getting a case with more airflow did help the difference was nowhere near as drastic as when I changed CPU coolers.

That is only 3 degrees less than your initial question.
If you get the thermal paste on either too thick or too thin it wont work very well.
Its tricky to do.
It should be basically about 1mm thick when everything is in place.