Problems with Overheating Processor

System Specifications:
Intel Core i5 760
Gigabyte P55-USB3
2x Corsair 2GB RAM
Radeon HD 6850
Rosewill RG630-S12 630W

I recently cleaned my case of all dust and accidentally removed my heat sink from the processor. Therefore, I purchased a generic brand thermal paste at Best Buy for a quick fix. I cleaned the surface of the processor and the heat sink with isopropyl alcohol and ensured it was shiny and clean. I applied about 'a grain of rice' of the thermal paste and installed the heat sink.

Now, when I open my bios on my computer, it is registering the processor at 88 degrees Celsius. This is a ludicrous number for even when running a very high processing program. Is it because of the low-grade thermal paste? I feel like it shouldn't be that high. Also, using CPUID HWMonitor, the average temperate is around 50 degrees Celsius when idling. I feel like even this may seem a bit high.

Please help,
Blix